1. Field of the Invention
This invention pertains to large reels such as those used to store long hoses of several hundred feet or more in length, and more particularly, it relates to a coupling mechanism for selectively engaging or disengaging the reel and a motorized drive train.
2. Description of the Prior Art
Present hose reels are normally equipped with either manual crank drives or electrical drives. However, most lower priced electrical drive reels are not equipped with enough power to adequately handle the heavy loads associated with hose reels that hold several hundred feet of hose, such reels requiring very large forces to pull the great lengths of hose. Consequently, even those hose reels driven by an electric motor must be assisted manually in many cases. Larger motors could be utilized, but in view of various physical and economical limitations their use is generally not practical. Thus, it is normally necessary to greatly gear down the drive train to provide the requisite pulling force with the size of motor available.
Since many of the typical operations that utilize reels holding very long hoses require continued unrolling of the hose and the rerolling of the hose on the reel several times in one day, serious operator fatigue usually results for, even with a motor, the operator must be continually assisting in the rerolling operation of the reel.
As pointed out, one partial solution to the problem of finding an inexpensive operator assist in hose reeling operations has been the use of a gear-down arrangement with a small electric motor to allow the motor to help to roll the hose onto the reel. Because of their high power output, permanent magnet DC motors are much more desirable than wound rotor motors for this type of operation. A problem remains, however, with respect to the high ratio reduction drive because of the large drag force encountered upon the rotation of the drum when the motor is not being used and as the operator unrolls the hose from the reel. This is the result of the permanent magnet effect of the DC motor amplified many times through the drive train.
It is, therefore, highly desirable to have a means for disconnecting the DC drive motor during unreeling operations where the operator wishes to maintain full control of the operation by pulling the required length of hose when and where he needs it. Clutches and other decoupling devices which have been heretofore used for such a purpose are generally complicated and relatively expensive mechanisms.